1. Field of the Invention
The present invention is directed to methods and systems for introducing additives to the combustion chamber of an engine via the air-intake system.
2. Description of the Related Technology
Additives are traditionally added to fuel before the fuel is pumped into fuel tanks of vehicles or other devices. An additive package formulated in this manner commonly experiences a full range of environmental conditions over an extended storage period. The fuel/additive mixture must remain essentially homogeneous throughout the transport, handling and storage period and thus must be formulated to endure extreme heat and cold, varying levels of humidity, etc. Further, the additive package must deliver a wide variety of components, which must be compatible with each other in order to be formulated in the fuel. Further, some additives may cause harm to fuel tanks or the fuel delivery system, e.g. damage to seals and gaskets. These problems often place significant constraints on an additive destined for use in fuel.
Other limitations on formulation of fuel additives also exist. For example, fuel formulators may not want to include certain additives in a particular fuel due to the increased cost of the fuel as a result of including the additive. Further, fuel formulators may introduce their own components into a fuel or particular fuels may contain potentially reactive species raising further compatibility problems for introduction of other additives which may potentially react with such components. For example, fuels may contain reactive species such as ethanol, ethers, fatty acid esters, acidic corrosion inhibitors, drag-reducing polymers, phenol antioxidants, wax anti-settling additives, cloud point reducers, aromatic amines, organic nitrates, organometallic octane enhancers and reactive dienes, thiophenes, peroxides and polynuclear aromatics. Also, additives can be rejected by fuel formulators when the desired treat rate in the fuel exceeds the capacity of the fuel additive addition systems located at a fuel terminal.
As discussed above, some very desirable additives are less than optimal when used in fuel additive formulations. These fuel additives or blend agents have yet to realize their full potential. Some examples of such restrictions are discussed for example in U.S. Pat. No. 7,846,224 where it is indicated that some friction modifiers may be incompatible with, or insoluble in the fuel or other additives likely to be in the fuel at low temperature. Wax-like materials are excellent friction modifiers, but have limited solubility in fuels.
There are some known methods that involve the introduction of certain compositions into the air-intake system of engines. Examples of such methods can be found, for example, in U.S. Pat. Nos. 4,377,135; 7,146,938; 5,282,445; 6,152,099; and 6,523,530.
These prior art methods are, for the most part, not directed to solving or avoiding the compatibility or solubility problems that may be encountered when formulating fuel additives into a fuel. In addition, the control mechanisms used in many of these prior art methods suffer from significant drawbacks and thus are not generally suitable for controlling the amount, aerosol particle size and/or timing of the additives being introduced into air-intake system in order to provide the most benefit.